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1 AFRL-OSR-VA-TR EPITAXIAL GRAPHENE QUANTUM ELECTRONICS Walter De Heer GEORGIA TECH RESEARCH CORPORATION 05/19/2014 Final Report DISTRIBUTION A: Distribution approved for public release Air Force Research Laboratory AF Office Of Scientific Research (AFOSR)/ RTB Arlington, Virginia Air Force Materiel Command

2 REPORT DOCUMENTATION PAGE Form Approved OMB No Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports ( ), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS 1 REPORT DATE (DD-MM-YYYY) 2 REPORT TYPE 3 DATES COVERED (From - To) Final 01-JUL-2010 to 31-DEC TITLE AND SUBTITLE 5a CONTRACT NUMBER Epitaxial Graphene Quantum Electronics FA b GRANT NUMBER 5c PROGRAM ELEMENT NUMBER 6 AUTHOR(S) 5d PROJECT NUMBER Walter A de Heer 4106C15 5e TASK NUMBER 5f WORK UNIT NUMBER 7 PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8 PERFORMING ORGANIZATION REPORT NUMBER School of Physics, Georgia Institute of Technology Atlanta GA NA 9 SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10 SPONSOR/MONITOR S ACRONYM(S) AIR FORCE OFFICE OF SCIENTIFIC RES/AFOSR/ARLINGTON, VA 11 SPONSOR/MONITOR S REPORT NUMBER(S) 12 DISTRIBUTION / AVAILABILITY STATEMENT 13 SUPPLEMENTARY NOTES 14 ABSTRACT Under the NSSEFF grant, we have accomplished several of the most important experimental results in graphene to date The epitaxial graphene route that we have pursued since 2001 has fully lived up to its expectations As we stated in our original proposal, we hoped to duplicate the transport properties that we had observed in carbon nanotubes, 15 years ago, in graphene In the past three years, we have achieved close to all that we proposed and more *We have discovered nanotube-like ballistic transport in graphene nanoribbons * We demonstrated a novel form or transport in these ribbons, involving a single channel and we possibly may have discovered non-conventional, short-lived charge carriers (trions) * We demonstrated one-dimensional ferromagnetism with spintronics potential * We have achieved the highest operational frequency in graphene transistors 15 SUBJECT TERMS Epitaxial graphene; quantum transport; nanoelectronics 16 SECURITY CLASSIFICATION OF: 17 LIMITATION OF ABSTRACT 18 NUMBER OF PAGES 19a NAME OF RESPONSIBLE PERSON a REPORT b ABSTRACT c THIS PAGE 19b TELEPHONE NUMBER (include area code) 3 Walter A de Heer Standard Form 298 (Re v 8-98) Prescribed by ANSI Std Z3918

3 National Security Science and Engineering Fellowship (NSSEFF) Supported by the National Defense Education Program (NDEP) Report Activity through December 2013 NAME: Walt A de Heer START DATE:July TITLE: Professor of Physics END DATE:Dec INSTITUTION: Georgia Institute of Technology PROJECT TITLE: NDEP/NSSEFF - Epitaxial Graphene Quantum Electronics Please include a current copy of your vitae with your report 1 Peer-reviewed publications a In preparation 2 c Submitted 3 b Accepted d published 48 Presentations DoD-related a DoD research audiences b General DoD audiences/events 4 Conferences/Meetings a Local/regional Total: Invited: audiences b National meetings Total:13 Invited:13 c International Total:9 Invited:9 meetings 3 Researchers supported a Undergraduate students 3 b Graduate students 4 c Post-docs 1 4 Patents a Filed 3 b Received 0 5 Subsequent Funding Have you applied for additional research funds as a result of the work you have done on your NSSEFF grant? If so, please indicate to where you made your application, the amount requested, and the status of each funding request Add lines as needed NSSEFF Activity Report 1 Source Amount Requested Current Status (3/2014) MRSEC 100 k/year Sept 2009 Sept 2014 AFOSR (this grant) 300 k/year Jul 2010 to Dec 2013 AFOSR (renewal grant) 200 k/year Sept 2013-Sept 2016 Pre-proposal to Moore Foundation 300 k/year Requested Jan 2015-Jan 2019 Super Seed /Michigan MRSEC 100 k/year Requested Sept 2014-Sept 2017

4 For the following questions, please use as much space as necessary to answer each item As appropriate, bullet lists are sufficient 6 Since the start of your NSSEFF grant, what interactions have you had with the Department of Defense? (ie, visiting DoD facilities, collaborating with DoD, and/or bringing DoD personnel to campus or other events, etc) Interactions have been limited to annual AFOSR contractor meetings 7 Since the start of your NSSEFF grant what new discoveries have you had and how might these be connected to issues that the general US public might be concerned with? Please list bullet points for a general non-scientific audience Our research focuses on a new form of electronics based on graphene This innovative direction has been pursued by my group since 2001 predating all other graphene work world wide Graphene based electronics is now seen as one of the most promising new directions in electronics research *Our most important discovery is the observation of essentially resistanceless graphene wires that are patterned on silicon carbide (Silicon carbide is an electronic material that has been pioneered by AFORS researcher for over 2 decades) This discovery will fundamentally impact both graphene electronics as well as basic science The paper has been published in Nature in Feb 2014 In more technical terms We have discovered single channel ballistic transport in graphene nanoribbons including a variety of new phenomena Resistances are found to be below 1 Ohm per square, 1000 times smaller than in conventional graphene We further have discovered that ballistic channel is spin polarized and a onedimensional ferromagnet This is an important discovery with implications for spintronics * We have found that ballistic transport most likely involves non-conventional charge carriers with finite life times We speculate that the charge carriers are not electrons, but rather particles that are composed of several electrons and holes This extremely interesting new avenue is now under investigation and is expected to have important consequences in the realm of transport in neutral graphene * We have discovered essentially reflectionless tunneling across physical nanogaps cut across graphene nanoribbons This manifestation of Klein tunneling is observed even at room temperature and will facilitate so-called ultrathin body field effect transistors, to be the at the heart of a promising ultrahigh frequency technology for digital applications This is work in progresss *We have found a new form of semiconducting graphene (also on silicon carbide), consisting of a graphene layer that is covalently bonded to the silicon terminated face of silicon carbide While this socalled buffer layer was known, its semiconducting properties were not exploited (or realized) We have produced field effect devices that use this material as the semiconductor, thereby making an important inroad to all graphene digital electronics This work is still in progress NSSEFF Activity Report 2

5 8 Awards and honors since receiving the NSSEFF grant Please indicate the year in which each award/honor was bestowed 1 MRS medal for pioneering research in graphene electronics (2010) 2 Utz- Hellmuth Felcht Award for the invention of graphene based electronics (2011) 3 J W Beams Award for achievements in Physics (2012) 9 To what extent has the NSSEFF grant enabled DOMESTIC collaborations, discovery, innovation, new experiences, sabbaticals, and/or other professional development? My NSSEFF grant (330 k/year for 3 years) has enabled fundamental research that has greatly contributed to the important discoveries listed above The funding was used to support students, purchase materials and supplies, and to travel in order to present the results at national and international meetings Undergraduate, graduate and postdoctoral students have benefitted immensely from the experience of participating in world-class pioneering research Our most recent research is showing that epitaxial graphene nanoelectronics may be realized relatively soon We hope to demonstrate extreme frequency transistors in the near future 10 To what extent has the NSSEFF grant enabled INTERNATIONAL collaborations, discovery, innovation, new experiences, sabbaticals, and/or other professional development? Some funding has been used for participation in international meetings Several international collaborations, primarily with researchers in France (CNRS Grenoble and the Soleil synchrotron facility in Paris) Some funding was also used to support the international STEG conference series (Science and Technology of Epitaxial Graphene) that is organized by me and Dr Claire Berger (scientific researcher in my group) 11 Photos please submit a recent photo of yourself and, if possible, of your research group Also, submit graphics related to your work funded by NSSEFF that are appropriate for general audiences (See PPT files) 12 Link to your lab s webpage: NSSEFF Activity Report 3